Fig. REF  shows corresponding escape
trajectories at \(\eta \ne 0\) , originating in very close neighborhoods
of the stable fixed points. It can be seen that escapes originating
close to the diagonal, as they approach the saddle, diverge and that
escapes from the two fixed points run parallel. Their line of
convergence is the escape separatrix shown in dashed red in
Fig. REF  and also in
Fig. REF . It is clear that the
escape separatrix is the locus of points with equal probability to be
reached from either fixed point [1]}, because
the probabilities on this curve are conditional upon reaching the
saddle, for which the probability is the same from either fixed point
by the construction (REF ) of the effective
potential. Because the conjugate momentum field \(\eta \)  is continuous
across this curve, \(- \int \eta \, dn\)  converges to the
log-probability along the separatrix from either side.
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